2020MNRAS.497L...1W

We explore the accretion states of tidal disruption events (TDEs) using a sample of seven X-ray bright sources. To this end, we estimate the relative contribution of the disc and corona to the observed X-ray emission through spectral modelling, and assess the X-ray brightness (through α_ox, L_2 keV_, and f_Edd,X) as a function of the Eddington ratio. We report strong positive correlations between α_ox and f_Edd,bol; f_Edd,X and f_Edd,UV; and an anticorrelation for L_2 keV_ and f_Edd,UV. TDEs at high f_Edd,bol have thermal dominated X-ray spectra and high (soft) α_ox, whereas those at low f_Edd,bol show a significant power-law contribution and low (hard) α_ox. Similar to X-ray binaries and active galactic nuclei, the transition between X-ray spectral states occurs around f_Edd,bol ≃ 0.03, although the uncertainty is large due to the small sample size. Our results suggest that X-ray surveys are more likely to discover TDEs at low f_Edd,bol, whereas optical surveys are more sensitive to TDEs at high Eddington ratios. The X-ray and optical selected TDEs have different UV and X-ray properties, which should be taken into account when deriving rates, luminosity, and black hole mass functions.